15% lower Dementia risk? What new study says about statins and diabetes

The burden of dementia is projected to rise with the ageing population. With no effective treatments, prevention is an urgent priority. According to the Lancet Commission, nearly half of cases of dementia could be theoretically prevented by eliminating 14 risk factors.

“Detecting and treating high levels of low-density lipoprotein cholesterol (LDL-C) from midlife is one such highlighted risk factor,” explained presenter, Doctor Tummas Ternhamar from Copenhagen University Hospital, Denmark. He noted that this could be particularly important in patients with type 2 diabetes since elevated LDL-C occurs frequently in these individuals and diabetes is a highlighted risk factor for cognitive decline and dementia.

“We hypothesised that early initiation of LDL-C-lowering statins following type 2 diabetes diagnosis could be associated with a lower risk of dementia,” said Doctor Ternhamar. “And we tested this in a large nationwide study using analysis methods to emulate a randomised trial and reduce some of the bias associated with observational studies,” he noted.

From Danish registers, 132,585 statin-naïve individuals were identified who developed type 2 diabetes from 2006 through to 2019, with follow-up until the end of 2021. Medical records were searched for diagnoses of all-cause dementia.

A clone-censor-weight design was used to analyse dementia incidence in patients with no statin initiated within five years after diagnosis, in those with early statin initiation within one year and in those with late statin initiation between one and five years after diagnosis. 

During a median follow-up of 7.1 years, 2.7% of patients developed dementia. Compared with no statin initiation, early statin treatment was associated with a 15% lower relative risk of dementia over 10 years.

Late statin initiation was associated with a 10% lower relative risk of dementia over 10 years. The results were similar in women and men.

Doctor Ternhamar concluded: “In individuals developing type 2 diabetes, statins were associated with a lower risk of dementia, most pronounced in those with early initiation. Statins seem to be underused in patients with type 2 diabetes, despite their protective effects against cardiovascular disease. Our findings suggest another potentially important reason to ensure that patients with type 2 diabetes and high LDL-C receive timely statin treatment.”

Commenting on the findings, Professor Isabel Goncalves, Member of the ESC Communication Committee, said: "People with type 2 diabetes already have a higher risk of dementia and are advised to lower cholesterol to reduce their risk of heart attack and stroke. This study suggests that starting statins soon after a type 2 diabetes diagnosis may also be linked to a modest reduction in dementia risk, with greater benefit than delaying treatment. Because statins are widely available and inexpensive, the findings are potentially important. However, this was an observational study, so it cannot prove that statins prevent dementia. The results should therefore support further research and help inform discussions between patients and clinicians."